COMMON: Move SCI's DCL decompression code to common

svn-id: r55367

3 files changed, 484 insertions, 0 deletions

diff --git a/common/dcl.cpp b/common/dcl.cpp
new file mode 100644
index 0000000000..ef45bc92ba
--- /dev/null
+++ b/common/dcl.cpp
@@ -0,0 +1,432 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#include "common/dcl.h"
+#include "common/debug.h"
+#include "common/debug-channels.h"
+#include "common/endian.h"
+#include "common/memstream.h"
+#include "common/stream.h"
+#include "common/util.h"
+
+namespace Common {
+
+class DecompressorDCL {
+public:
+	bool unpack(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked);
+
+protected:
+	/**
+	 * Initialize decompressor.
+	 * @param src		source stream to read from
+	 * @param dest		destination stream to write to
+	 * @param nPacked	size of packed data
+	 * @param nUnpacket	size of unpacked data
+	 * @return 0 on success, non-zero on error
+	 */
+	void init(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked);
+
+	/**
+	 * Get a number of bits from _src stream, starting with the least
+	 * significant unread bit of the current four byte block.
+	 * @param n		number of bits to get
+	 * @return n-bits number
+	 */
+	uint32 getBitsLSB(int n);
+
+	/**
+	 * Get one byte from _src stream.
+	 * @return byte
+	 */
+	byte getByteLSB();
+
+	void fetchBitsLSB();
+
+	/**
+	 * Write one byte into _dest stream
+	 * @param b byte to put
+	 */
+	void putByte(byte b);
+
+	int huffman_lookup(const int *tree);
+
+	uint32 _dwBits;		///< bits buffer
+	byte _nBits;		///< number of unread bits in _dwBits
+	uint32 _szPacked;	///< size of the compressed data
+	uint32 _szUnpacked;	///< size of the decompressed data
+	uint32 _dwRead;		///< number of bytes read from _src
+	uint32 _dwWrote;	///< number of bytes written to _dest
+	Common::ReadStream *_src;
+	byte *_dest;
+};
+
+void DecompressorDCL::init(Common::ReadStream *src, byte *dest, uint32 nPacked,
+                        uint32 nUnpacked) {
+	_src = src;
+	_dest = dest;
+	_szPacked = nPacked;
+	_szUnpacked = nUnpacked;
+	_nBits = 0;
+	_dwRead = _dwWrote = 0;
+	_dwBits = 0;
+}
+
+void DecompressorDCL::fetchBitsLSB() {
+	while (_nBits <= 24) {
+		_dwBits |= ((uint32)_src->readByte()) << _nBits;
+		_nBits += 8;
+		_dwRead++;
+	}
+}
+
+uint32 DecompressorDCL::getBitsLSB(int n) {
+	// fetching more data to buffer if needed
+	if (_nBits < n)
+		fetchBitsLSB();
+	uint32 ret = (_dwBits & ~((~0) << n));
+	_dwBits >>= n;
+	_nBits -= n;
+	return ret;
+}
+
+byte DecompressorDCL::getByteLSB() {
+	return getBitsLSB(8);
+}
+
+void DecompressorDCL::putByte(byte b) {
+	_dest[_dwWrote++] = b;
+}
+
+#define HUFFMAN_LEAF 0x40000000
+// Branch node
+#define BN(pos, left, right)  ((left << 12) | (right)),
+// Leaf node
+#define LN(pos, value)  ((value) | HUFFMAN_LEAF),
+
+static const int length_tree[] = {
+	BN(0, 1, 2)
+	BN(1, 3, 4)     BN(2, 5, 6)
+	BN(3, 7, 8)     BN(4, 9, 10)    BN(5, 11, 12)  LN(6, 1)
+	BN(7, 13, 14)   BN(8, 15, 16)   BN(9, 17, 18)  LN(10, 3)  LN(11, 2)  LN(12, 0)
+	BN(13, 19, 20)  BN(14, 21, 22)  BN(15, 23, 24) LN(16, 6)  LN(17, 5)  LN(18, 4)
+	BN(19, 25, 26)  BN(20, 27, 28)  LN(21, 10)     LN(22, 9)  LN(23, 8)  LN(24, 7)
+	BN(25, 29, 30)  LN(26, 13)      LN(27, 12)     LN(28, 11)
+	LN(29, 15)      LN(30, 14)
+	0 // We need something witout a comma at the end
+};
+
+static const int distance_tree[] = {
+	BN(0, 1, 2)
+	BN(1, 3, 4)       BN(2, 5, 6)
+	//
+	BN(3, 7, 8)       BN(4, 9, 10)      BN(5, 11, 12)     LN(6, 0)
+	BN(7, 13, 14)     BN(8, 15, 16)     BN(9, 17, 18)     BN(10, 19, 20)
+	BN(11, 21, 22)    BN(12, 23, 24)
+	//
+	BN(13, 25, 26)    BN(14, 27, 28)    BN(15, 29, 30)    BN(16, 31, 32)
+	BN(17, 33, 34)    BN(18, 35, 36)    BN(19, 37, 38)    BN(20, 39, 40)
+	BN(21, 41, 42)    BN(22, 43, 44)    LN(23, 2)         LN(24, 1)
+	//
+	BN(25, 45, 46)    BN(26, 47, 48)    BN(27, 49, 50)    BN(28, 51, 52)
+	BN(29, 53, 54)    BN(30, 55, 56)    BN(31, 57, 58)    BN(32, 59, 60)
+	BN(33, 61, 62)	  BN(34, 63, 64)    BN(35, 65, 66)    BN(36, 67, 68)
+	BN(37, 69, 70)    BN(38, 71, 72)    BN(39, 73, 74)    BN(40, 75, 76)
+	LN(41, 6)         LN(42, 5)         LN(43, 4)         LN(44, 3)
+	//
+	BN(45, 77, 78)    BN(46, 79, 80)    BN(47, 81, 82)    BN(48, 83, 84)
+	BN(49, 85, 86)    BN(50, 87, 88)    BN(51, 89, 90)    BN(52, 91, 92)
+	BN(53, 93, 94)    BN(54, 95, 96)    BN(55, 97, 98)    BN(56, 99, 100)
+	BN(57, 101, 102)  BN(58, 103, 104)  BN(59, 105, 106)  BN(60, 107, 108)
+	BN(61, 109, 110)  LN(62, 21)        LN(63, 20)        LN(64, 19)
+	LN(65, 18)        LN(66, 17)        LN(67, 16)        LN(68, 15)
+	LN(69, 14)        LN(70, 13)        LN(71, 12)        LN(72, 11)
+	LN(73, 10)        LN(74, 9)         LN(75, 8)         LN(76, 7)
+	//
+	BN(77, 111, 112)  BN(78, 113, 114)  BN(79, 115, 116)  BN(80, 117, 118)
+	BN(81, 119, 120)  BN(82, 121, 122)  BN(83, 123, 124)  BN(84, 125, 126)
+	LN(85, 47)        LN(86, 46)        LN(87, 45)        LN(88, 44)
+	LN(89, 43)        LN(90, 42)        LN(91, 41)        LN(92, 40)
+	LN(93, 39)        LN(94, 38)        LN(95, 37)        LN(96, 36)
+	LN(97, 35)        LN(98, 34)        LN(99, 33)        LN(100, 32)
+	LN(101, 31)       LN(102, 30)       LN(103, 29)       LN(104, 28)
+	LN(105, 27)       LN(106, 26)       LN(107, 25)       LN(108, 24)
+	LN(109, 23)       LN(110, 22)       LN(111, 63)       LN(112, 62)
+	LN(113, 61)       LN(114, 60)       LN(115, 59)       LN(116, 58)
+	LN(117, 57)       LN(118, 56)       LN(119, 55)       LN(120, 54)
+	LN(121, 53)       LN(122, 52)       LN(123, 51)       LN(124, 50)
+	LN(125, 49)       LN(126, 48)
+	0 // We need something witout a comma at the end
+};
+
+static const int ascii_tree[] = {
+	BN(0, 1, 2)       BN(1, 3, 4)       BN(2, 5, 6)       BN(3, 7, 8)
+	BN(4, 9, 10)      BN(5, 11, 12)     BN(6, 13, 14)     BN(7, 15, 16)
+	BN(8, 17, 18)     BN(9, 19, 20)     BN(10, 21, 22)    BN(11, 23, 24)
+	BN(12, 25, 26)    BN(13, 27, 28)    BN(14, 29, 30)    BN(15, 31, 32)
+	BN(16, 33, 34)    BN(17, 35, 36)    BN(18, 37, 38)    BN(19, 39, 40)
+	BN(20, 41, 42)    BN(21, 43, 44)    BN(22, 45, 46)    BN(23, 47, 48)
+	BN(24, 49, 50)    BN(25, 51, 52)    BN(26, 53, 54)    BN(27, 55, 56)
+	BN(28, 57, 58)    BN(29, 59, 60)    LN(30, 32)
+	//
+	BN(31, 61, 62)    BN(32, 63, 64)    BN(33, 65, 66)    BN(34, 67, 68)
+	BN(35, 69, 70)    BN(36, 71, 72)    BN(37, 73, 74)    BN(38, 75, 76)
+	BN(39, 77, 78)    BN(40, 79, 80)    BN(41, 81, 82)    BN(42, 83, 84)
+	BN(43, 85, 86)    BN(44, 87, 88)    BN(45, 89, 90)    BN(46, 91, 92)
+	BN(47, 93, 94)    BN(48, 95, 96)    BN(49, 97, 98)    LN(50, 117)
+	LN(51, 116)       LN(52, 115)       LN(53, 114)       LN(54, 111)
+	LN(55, 110)       LN(56, 108)       LN(57, 105)       LN(58, 101)
+	LN(59, 97)        LN(60, 69)
+	//
+	BN(61, 99, 100)   BN(62, 101, 102)  BN(63, 103, 104)  BN(64, 105, 106)
+	BN(65, 107, 108)  BN(66, 109, 110)	BN(67, 111, 112)  BN(68, 113, 114)
+	BN(69, 115, 116)  BN(70, 117, 118)  BN(71, 119, 120)  BN(72, 121, 122)
+	BN(73, 123, 124)  BN(74, 125, 126)  BN(75, 127, 128)  BN(76, 129, 130)
+	BN(77, 131, 132)  BN(78, 133, 134)  LN(79, 112)       LN(80, 109)
+	LN(81, 104)       LN(82, 103)       LN(83, 102)       LN(84, 100)
+	LN(85, 99)        LN(86, 98)        LN(87, 84)        LN(88, 83)
+	LN(89, 82)        LN(90, 79)        LN(91, 78)        LN(92, 76)
+	LN(93, 73)        LN(94, 68)        LN(95, 67)        LN(96, 65)
+	LN(97, 49)        LN(98, 45)
+	//
+	BN(99, 135, 136)  BN(100, 137, 138) BN(101, 139, 140) BN(102, 141, 142)
+	BN(103, 143, 144) BN(104, 145, 146)	BN(105, 147, 148) BN(106, 149, 150)
+	BN(107, 151, 152) BN(108, 153, 154) BN(109, 155, 156) BN(110, 157, 158)
+	BN(111, 159, 160) BN(112, 161, 162) BN(113, 163, 164) LN(114, 119)
+	LN(115, 107)      LN(116, 85)       LN(117, 80)       LN(118, 77)
+	LN(119, 70)       LN(120, 66)       LN(121, 61)       LN(122, 56)
+	LN(123, 55)       LN(124, 53)       LN(125, 52)       LN(126, 51)
+	LN(127, 50)       LN(128, 48)       LN(129, 46)       LN(130, 44)
+	LN(131, 41)       LN(132, 40)       LN(133, 13)       LN(134, 10)
+	//
+	BN(135, 165, 166) BN(136, 167, 168) BN(137, 169, 170) BN(138, 171, 172)
+	BN(139, 173, 174) BN(140, 175, 176) BN(141, 177, 178) BN(142, 179, 180)
+	BN(143, 181, 182) BN(144, 183, 184) BN(145, 185, 186) BN(146, 187, 188)
+	BN(147, 189, 190) BN(148, 191, 192) LN(149, 121)      LN(150, 120)
+	LN(151, 118)      LN(152, 95)       LN(153, 91)       LN(154, 87)
+	LN(155, 72)       LN(156, 71)       LN(157, 58)       LN(158, 57)
+	LN(159, 54)       LN(160, 47)       LN(161, 42)       LN(162, 39)
+	LN(163, 34)       LN(164, 9)
+	//
+	BN(165, 193, 194) BN(166, 195, 196) BN(167, 197, 198) BN(168, 199, 200)
+	BN(169, 201, 202) BN(170, 203, 204) BN(171, 205, 206) BN(172, 207, 208)
+	BN(173, 209, 210) BN(174, 211, 212) BN(175, 213, 214) BN(176, 215, 216)
+	BN(177, 217, 218) BN(178, 219, 220) BN(179, 221, 222) BN(180, 223, 224)
+	BN(181, 225, 226) BN(182, 227, 228)	BN(183, 229, 230) BN(184, 231, 232)
+	BN(185, 233, 234) LN(186, 93)       LN(187, 89)       LN(188, 88)
+	LN(189, 86)       LN(190, 75)       LN(191, 62)       LN(192, 43)
+	//
+	BN(193, 235, 236) BN(194, 237, 238) BN(195, 239, 240) BN(196, 241, 242)
+	BN(197, 243, 244) BN(198, 245, 246)	BN(199, 247, 248) BN(200, 249, 250)
+	BN(201, 251, 252) BN(202, 253, 254) BN(203, 255, 256) BN(204, 257, 258)
+	BN(205, 259, 260) BN(206, 261, 262) BN(207, 263, 264) BN(208, 265, 266)
+	BN(209, 267, 268) BN(210, 269, 270)	BN(211, 271, 272) BN(212, 273, 274)
+	BN(213, 275, 276) BN(214, 277, 278) BN(215, 279, 280) BN(216, 281, 282)
+	BN(217, 283, 284) BN(218, 285, 286) BN(219, 287, 288) BN(220, 289, 290)
+	BN(221, 291, 292) BN(222, 293, 294) BN(223, 295, 296) BN(224, 297, 298)
+	BN(225, 299, 300) BN(226, 301, 302) BN(227, 303, 304) BN(228, 305, 306)
+	BN(229, 307, 308) LN(230, 122)      LN(231, 113)      LN(232, 38)
+	LN(233, 36)       LN(234, 33)
+	//
+	BN(235, 309, 310) BN(236, 311, 312) BN(237, 313, 314) BN(238, 315, 316)
+	BN(239, 317, 318) BN(240, 319, 320) BN(241, 321, 322) BN(242, 323, 324)
+	BN(243, 325, 326) BN(244, 327, 328) BN(245, 329, 330) BN(246, 331, 332)
+	BN(247, 333, 334) BN(248, 335, 336) BN(249, 337, 338) BN(250, 339, 340)
+	BN(251, 341, 342) BN(252, 343, 344)	BN(253, 345, 346) BN(254, 347, 348)
+	BN(255, 349, 350) BN(256, 351, 352) BN(257, 353, 354) BN(258, 355, 356)
+	BN(259, 357, 358) BN(260, 359, 360) BN(261, 361, 362) BN(262, 363, 364)
+	BN(263, 365, 366) BN(264, 367, 368) BN(265, 369, 370) BN(266, 371, 372)
+	BN(267, 373, 374) BN(268, 375, 376) BN(269, 377, 378) BN(270, 379, 380)
+	BN(271, 381, 382) BN(272, 383, 384) BN(273, 385, 386) BN(274, 387, 388)
+	BN(275, 389, 390) BN(276, 391, 392) BN(277, 393, 394) BN(278, 395, 396)
+	BN(279, 397, 398) BN(280, 399, 400) BN(281, 401, 402) BN(282, 403, 404)
+	BN(283, 405, 406) BN(284, 407, 408) BN(285, 409, 410) BN(286, 411, 412)
+	BN(287, 413, 414) BN(288, 415, 416) BN(289, 417, 418) BN(290, 419, 420)
+	BN(291, 421, 422) BN(292, 423, 424) BN(293, 425, 426) BN(294, 427, 428)
+	BN(295, 429, 430) BN(296, 431, 432) BN(297, 433, 434) BN(298, 435, 436)
+	LN(299, 124)      LN(300, 123)      LN(301, 106)      LN(302, 92)
+	LN(303, 90)       LN(304, 81)       LN(305, 74)       LN(306, 63)
+	LN(307, 60)       LN(308, 0)
+	//
+	BN(309, 437, 438) BN(310, 439, 440) BN(311, 441, 442) BN(312, 443, 444)
+	BN(313, 445, 446) BN(314, 447, 448) BN(315, 449, 450) BN(316, 451, 452)
+	BN(317, 453, 454) BN(318, 455, 456) BN(319, 457, 458) BN(320, 459, 460)
+	BN(321, 461, 462) BN(322, 463, 464) BN(323, 465, 466) BN(324, 467, 468)
+	BN(325, 469, 470) BN(326, 471, 472)	BN(327, 473, 474) BN(328, 475, 476)
+	BN(329, 477, 478) BN(330, 479, 480) BN(331, 481, 482) BN(332, 483, 484)
+	BN(333, 485, 486) BN(334, 487, 488) BN(335, 489, 490) BN(336, 491, 492)
+	BN(337, 493, 494) BN(338, 495, 496) BN(339, 497, 498) BN(340, 499, 500)
+	BN(341, 501, 502) BN(342, 503, 504) BN(343, 505, 506) BN(344, 507, 508)
+	BN(345, 509, 510) LN(346, 244)      LN(347, 243)      LN(348, 242)
+	LN(349, 238)      LN(350, 233)      LN(351, 229)      LN(352, 225)
+	LN(353, 223)      LN(354, 222)      LN(355, 221)      LN(356, 220)
+	LN(357, 219)      LN(358, 218)      LN(359, 217)      LN(360, 216)
+	LN(361, 215)      LN(362, 214)      LN(363, 213)      LN(364, 212)
+	LN(365, 211)      LN(366, 210)      LN(367, 209)      LN(368, 208)
+	LN(369, 207)      LN(370, 206)      LN(371, 205)      LN(372, 204)
+	LN(373, 203)      LN(374, 202)      LN(375, 201)      LN(376, 200)
+	LN(377, 199)      LN(378, 198)      LN(379, 197)      LN(380, 196)
+	LN(381, 195)      LN(382, 194)      LN(383, 193)      LN(384, 192)
+	LN(385, 191)      LN(386, 190)      LN(387, 189)      LN(388, 188)
+	LN(389, 187)      LN(390, 186)      LN(391, 185)      LN(392, 184)
+	LN(393, 183)      LN(394, 182)      LN(395, 181)      LN(396, 180)
+	LN(397, 179)      LN(398, 178)      LN(399, 177)      LN(400, 176)
+	LN(401, 127)      LN(402, 126)      LN(403, 125)      LN(404, 96)
+	LN(405, 94)       LN(406, 64)       LN(407, 59)       LN(408, 37)
+	LN(409, 35)       LN(410, 31)       LN(411, 30)       LN(412, 29)
+	LN(413, 28)       LN(414, 27)       LN(415, 25)       LN(416, 24)
+	LN(417, 23)       LN(418, 22)       LN(419, 21)       LN(420, 20)
+	LN(421, 19)       LN(422, 18)       LN(423, 17)       LN(424, 16)
+	LN(425, 15)       LN(426, 14)       LN(427, 12)       LN(428, 11)
+	LN(429, 8)        LN(430, 7)        LN(431, 6)        LN(432, 5)
+	LN(433, 4)        LN(434, 3)        LN(435, 2)        LN(436, 1)
+	LN(437, 255)      LN(438, 254)      LN(439, 253)      LN(440, 252)
+	LN(441, 251)      LN(442, 250)      LN(443, 249)      LN(444, 248)
+	LN(445, 247)      LN(446, 246)      LN(447, 245)      LN(448, 241)
+	LN(449, 240)      LN(450, 239)      LN(451, 237)      LN(452, 236)
+	LN(453, 235)      LN(454, 234)      LN(455, 232)      LN(456, 231)
+	LN(457, 230)      LN(458, 228)      LN(459, 227)      LN(460, 226)
+	LN(461, 224)      LN(462, 175)      LN(463, 174)      LN(464, 173)
+	LN(465, 172)      LN(466, 171)      LN(467, 170)      LN(468, 169)
+	LN(469, 168)      LN(470, 167)      LN(471, 166)      LN(472, 165)
+	LN(473, 164)      LN(474, 163)      LN(475, 162)      LN(476, 161)
+	LN(477, 160)      LN(478, 159)      LN(479, 158)      LN(480, 157)
+	LN(481, 156)      LN(482, 155)      LN(483, 154)      LN(484, 153)
+	LN(485, 152)      LN(486, 151)      LN(487, 150)      LN(488, 149)
+	LN(489, 148)      LN(490, 147)      LN(491, 146)      LN(492, 145)
+	LN(493, 144)      LN(494, 143)      LN(495, 142)      LN(496, 141)
+	LN(497, 140)      LN(498, 139)      LN(499, 138)      LN(500, 137)
+	LN(501, 136)      LN(502, 135)      LN(503, 134)      LN(504, 133)
+	LN(505, 132)      LN(506, 131)      LN(507, 130)      LN(508, 129)
+	LN(509, 128)      LN(510, 26)
+};
+
+int DecompressorDCL::huffman_lookup(const int *tree) {
+	int pos = 0;
+
+	while (!(tree[pos] & HUFFMAN_LEAF)) {
+		int bit = getBitsLSB(1);
+		debug(8, "[%d]:%d->", pos, bit);
+		pos = bit ? tree[pos] & 0xFFF : tree[pos] >> 12;
+	}
+
+	debug(8, "=%02x\n", tree[pos] & 0xffff);
+	return tree[pos] & 0xFFFF;
+}
+
+#define DCL_BINARY_MODE 0
+#define DCL_ASCII_MODE 1
+
+bool DecompressorDCL::unpack(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked) {
+	init(src, dest, nPacked, nUnpacked);
+
+	int value;
+	uint32 val_distance, val_length;
+
+	int mode = getByteLSB();
+	int length_param = getByteLSB();
+
+	if (mode != DCL_BINARY_MODE && mode != DCL_ASCII_MODE) {
+		warning("DCL-INFLATE: Error: Encountered mode %02x, expected 00 or 01", mode);
+		return false;
+	}
+
+	if (length_param < 3 || length_param > 6)
+		warning("Unexpected length_param value %d (expected in [3,6])", length_param);
+
+	while (_dwWrote < _szUnpacked) {
+		if (getBitsLSB(1)) { // (length,distance) pair
+			value = huffman_lookup(length_tree);
+
+			if (value < 8)
+				val_length = value + 2;
+			else
+				val_length = 8 + (1 << (value - 7)) + getBitsLSB(value - 7);
+
+			debug(8, " | ");
+
+			value = huffman_lookup(distance_tree);
+
+			if (val_length == 2)
+				val_distance = (value << 2) | getBitsLSB(2);
+			else
+				val_distance = (value << length_param) | getBitsLSB(length_param);
+			val_distance ++;
+
+			debug(8, "\nCOPY(%d from %d)\n", val_length, val_distance);
+
+			if (val_length + _dwWrote > _szUnpacked) {
+				warning("DCL-INFLATE Error: Write out of bounds while copying %d bytes", val_length);
+				return false;
+			}
+
+			if (_dwWrote < val_distance) {
+				warning("DCL-INFLATE Error: Attempt to copy from before beginning of input stream");
+				return false;
+			}
+
+			while (val_length) {
+				uint32 copy_length = (val_length > val_distance) ? val_distance : val_length;
+				assert(val_distance >= copy_length);
+				uint32 pos = _dwWrote - val_distance;
+				for (uint32 i = 0; i < copy_length; i++)
+					putByte(dest[pos + i]);
+
+				for (uint32 i = 0; i < copy_length; i++)
+					debug(9, "\33[32;31m%02x\33[37;37m ", dest[pos + i]);
+				debug(9, "\n");
+
+				val_length -= copy_length;
+				val_distance += copy_length;
+			}
+
+		} else { // Copy byte verbatim
+			value = (mode == DCL_ASCII_MODE) ? huffman_lookup(ascii_tree) : getByteLSB();
+			putByte(value);
+			debug(9, "\33[32;31m%02x \33[37;37m", value);
+		}
+	}
+
+	return _dwWrote == _szUnpacked;
+}
+
+bool decompressDCL(ReadStream *src, byte *dest, uint32 packedSize, uint32 unpackedSize) {
+	if (!src || !dest)
+		return false;
+
+	DecompressorDCL dcl;
+	return dcl.unpack(src, dest, packedSize, unpackedSize);
+}
+
+SeekableReadStream *decompressDCL(ReadStream *src, uint32 packedSize, uint32 unpackedSize) {
+	byte *data = (byte *)malloc(unpackedSize);
+
+	if (decompressDCL(src, data, packedSize, unpackedSize))
+		return new MemoryReadStream(data, unpackedSize, DisposeAfterUse::YES);
+
+	free(data);
+	return 0;
+}
+
+} // End of namespace Common
diff --git a/common/dcl.h b/common/dcl.h
new file mode 100644
index 0000000000..54970fc864
--- /dev/null
+++ b/common/dcl.h
@@ -0,0 +1,51 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#ifndef COMMON_DCL_H
+#define COMMON_DCL_H
+
+#include "common/scummsys.h"
+
+namespace Common {
+
+class ReadStream;
+class SeekableReadStream;
+
+/**
+ * Try to decompress a PKWARE DCL compressed stream. Returns true if
+ * successful.
+ */
+bool decompressDCL(ReadStream *src, byte *dest, uint32 packedSize, uint32 unpackedSize);
+
+/**
+ * Try to decompress a PKWARE DCL compressed stream. Returns a valid pointer
+ * if successful and 0 otherwise.
+ */
+SeekableReadStream *decompressDCL(ReadStream *src, uint32 packedSize, uint32 unpackedSize);
+
+} // End of namespace Common
+
+#endif
+
diff --git a/common/module.mk b/common/module.mk
index 30684c0582..a4cea5c23f 100644
--- a/common/module.mk
+++ b/common/module.mk
@@ -4,6 +4,7 @@ MODULE_OBJS := \
 	archive.o \
 	config-file.o \
 	config-manager.o \
+	dcl.o \
 	debug.o \
 	error.o \
 	EventDispatcher.o \